AGING AND THE SOCIAL BRAIN: THE ROLE OF SOCIAL NETWORKS IN ALZHEIMER'S DISEASE AND RELATED DEMENTIAS

Abstract Research suggests social connectedness reduces dementia risk and helps older adults with neuropathology maintain cognitive functionality and quality of life. However, little is known about the specific underlying social and biological mechanisms. This presentation provides an overview of three promising pathways through social bridging (i.e., cognitive enrichment through expansive social networks), social bonding (i.e., neuroendocrine benefits of integration in cohesive social networks), and social stress (i.e., HPA axis dysregulation resulting from social losses, role exits, and dysfunction or strain in relationships). It discusses how personal social network methodology combined with tests of general and social cognitive function and/or biomarkers can identify specific etiological mechanisms. These insights can be leveraged to develop policies and programs that support brain health and cognitive function in older adults. This presentation sets the stage for the remainder of the symposium, which presents empirical findings examining these mechanisms from a social network perspective.

Hearing loss is highly prevalent but disparities exist in hearing care. Delivering care in partnership with community health workers (CHWs) is an established approach to addressing disparities but has not been robustly studied in hearing care. We recruited older adults with hearing loss from community sites in Baltimore, MD. The 2-hour intervention consists of fitting a low-cost amplification device and counseling.151 participants were randomized. The primary outcome was change in communication function (Hearing Handicap Inventory for the Elderly-Screening [HHIE-S]; range 0-40; higher scores indicate poorer function). Communication function significantly improved in the intervention group, with an intention to treat estimated average treatment effect of a -12.98 point change ). In the first randomized control trial of a CHWdelivered hearing care intervention for older adults using low-cost amplification devices, participants receiving the intervention demonstrated a treatment effect comparable to prior studies of conventional hearing aids fit by audiologists.

IT'S ABOUT WHO YOU KNOW: RELATIONSHIPS BETWEEN SOCIAL NETWORKS, COGNITIVE FUNCTION, AND BRAIN HEALTH IN LATER LIFE
Chair: Lucas Hamilton Discussant: Sara Moorman Evidence has been steadily increasing about the benefit of social connectedness for healthy aging. Yet, thanks to the complexity of human social interactions, it remains difficult to pinpoint specific benefits and mechanisms by which such benefits emerge. We offer this symposium to address this issue by presenting new findings from ongoing work at Indiana University in collaboration with the Indiana Alzheimer's Disease Research Center. First, an overview of recent literature will be presented alongside a brief introduction to egocentric network analysis and its utility in probing social determinants of health. Next, we turn our attention to characteristics of social networks and their importance for cognitive health in later life. Different types of social enrichment will be evaluated in terms of their respective influence on cognitive reserve (i.e., neuropsychological evaluations, brain health). Additional attention will be paid to the comparison of emotionally supportive (i.e., social bonding) and more informationally supportive (i.e., social bridging) ties as promoters of brain health. Then, the final talks will describe potential avenues for increasing social connectedness in older adulthood. Individual differences in social cognitive function, namely Theory of Mind (i.e., reading another person's thoughts, feelings, and intentions), has been implicated as mechanism by which older adults can maintain larger networks with more weak ties, in turn, promoting cognitive function. Separately, the presence of ambivalent ties (i.e., connections that beget positivity and negativity) may serve as a window of opportunity whereby older adults can leverage strengths in emotion regulation to maintain these ties without negative health consequences.

AGING AND THE SOCIAL BRAIN: THE ROLE OF SOCIAL NETWORKS IN ALZHEIMER'S DISEASE AND RELATED DEMENTIAS Brea Perry, Indiana University, Bloomington, Indiana, United States
Research suggests social connectedness reduces dementia risk and helps older adults with neuropathology maintain cognitive functionality and quality of life. However, little is known about the specific underlying social and biological mechanisms. This presentation provides an overview of three promising pathways through social bridging (i.e., cognitive enrichment through expansive social networks), social bonding (i.e., neuroendocrine benefits of integration in cohesive social networks), and social stress (i.e., HPA axis dysregulation resulting from social losses, role exits, and dysfunction or strain in relationships). It discusses how personal social network methodology combined with tests of general and social cognitive function and/or biomarkers can identify specific etiological mechanisms. These insights can be leveraged to develop policies and programs that support brain health and cognitive function in older adults. This presentation sets the stage for the remainder of the symposium, which presents empirical findings examining these mechanisms from a social network perspective. Social connectedness has been linked to decreased rates of cognitive decline in later life. However, recent work suggests that particular social network characteristics (i.e., bonding and bridging) may buffer against age-related degeneration. The present study analyzes social network and structural MRI data of 176 older adults from the Social Networks and Alzheimer's Disease (SNAD) study. Results indicate that increased social bridging is associated with greater grey matter (GM) volume in several limbic structures. Increased social bonding is associated with greater GM volumes in several cerebral cortex structures as well as greater volumes in some components of the limbic system. Most notably, the effects of bridging are primarily lateralized in the left hemisphere while the effects of bonding are observed mostly in the right hemisphere. These results suggest that the neurocognitive benefits of social connectedness depend on the preponderance of bridging and/or bonding ties in older adults' social networks.

LINKS BETWEEN SOCIAL CONNECTEDNESS AND COGNITIVE HEALTH OPERATE THROUGH SOCIAL STIMULATION AND COGNITIVE RESERVE
Siyun Peng 1 , Anmoldeep Singh 2 , Mohit Manchella 3 , and Brea Perry 1 , 1. Indiana University, Bloomington,Indiana,United States,2. Indiana University,Newburgh,Indiana,United States,3. University of Southern Indiana,Carmel,Indiana,United States The link between social connectedness and dementia risk and resilience has been examined using a diverse set of measures. Though different measures of connectedness reflect distinct social processes and underlying mechanisms (e.g., stress buffering, cognitive stimulation), few studies have compared them. Using data from two social network studies of older adults (N=283), we compare associations between 29 measures of social connectedness and general cognitive function (MoCA), and non-verbal (Rey) and episodic memory (Craft). Measures of social participation (e.g., volunteering, working, attending church) and social support were unassociated with cognitive outcomes, net of controls. Quality of friendships (p<.05), family relationships (p<.01), and marriage (p<.05) were sporadically associated. Measures indicating large, diverse, and expansive networks were strongly and consistently related to all cognitive outcomes (e.g.,  Anne Krendl, and Brea Perry, Indiana University, Bloomington, Indiana, United States Social connectedness confers benefits to older adults' cognition, including slowing the progression of Alzheimer's disease (AD). Social connectedness is facilitated by social cognitive function -how people understand, store, and apply information about others -which declines over the lifespan. We examined whether two core social cognitive skills -face memory and theory of mind (the ability to infer others' mental states) -predicted older adults' social network structure and composition. Cognitively normal older adults (OA; N=119) and OA with mild cognitive impairment (MCI) or AD (N=96) completed a social network interview, a face memory task, and a theory of mind measure. Social cognitive deficits were highest among OA with MCI and AD. Face memory predicted network size, whereas theory of mind predicted network composition. Neuroimaging results describing OA's social cognitive deficits are also discussed. Social cognitive function may be an important intervention target for preserving older adults' social connectedness.

TO LOVE AND LOATHE: EXAMINING THE COSTS AND BENEFITS OF AMBIVALENT TIES IN OLDER ADULTHOOD
Lucas Hamilton, Siyun Peng, Anne Krendl, and Brea Perry, Indiana University, Bloomington, Indiana, United States Ambivalent ties are relationships that offer support but beget stress, which generally has a detrimental impact on health. Existing theory suggests that older adults gradually remove such ties over time; however, it is not uncommon for ambivalence to exist in older adults' close relationships (i.e., partners, children). Social network data was used from 286 older adults with about half having mild cognitive impairment. Roughly two-thirds of the sample reported at least one ambivalent tie, most commonly partners, children, and friends. Logistic regressions revealed distinct characteristics of these ties. Participants who reported at least one ambivalent tie (most notably, partners and friends) had social networks with structures known to confer cognitive benefits. Importantly, these effects dissipate with diminished cognitive status. Altogether, ambivalent ties may confer benefits when resources are available to manage such relationships. When resources are taxed, however, ambivalent ties may contribute to cascading health declines.